This invention relates to a process of preventing stray currents in peripheral parts of a plant in an electrolysis, wherein an electrolyte line extends from the outlet of an electrolysis device to a collecting tank and from the same back to the inlet of the electrolysis device. Usually, the difference of the electric d.c. voltage between the electrolyte outlet line and the line leading to the inlet is at least 3 V and preferably at least 10 V.
In electrolysis plants, a so-called stray current flows through the electrolyte supply line and the electrolyte discharge line, outside the actual electrolysis device. This stray current causes an increased consumption of energy, and it may lead to corrosion problems in the peripheral parts of the plant, e.g. in the reservoir, in the electrolyte conditioning and in a usually present electrolyte preheater. Would the supply line and/or the discharge line be grounded, metal deposits in the line would occur in the vicinity of the grounding terminal, if it is a metal recovery or metal coating process (electroplating).
It is the object underlying the invention to simply and reliably prevent the current flowing through the supply line and the discharge line, so that even with relatively high electric voltages in the electrolysis device stray currents in the peripheral parts of the plant outside the electrolysis device are avoided. In accordance with the invention this is achieved in that the electrolyte is supplied from the outlet of the electrolysis device to a first container which is disposed at a higher level than a second container, that electrolyte collected in the first container is periodically discharged through a first syphon line into the second container, that electrolyte collected in the second container is periodically discharged through a second syphon line into a collecting tank which is disposed at a lower level than the second container, that the outlet end of each syphon line is disposed at a distance above the liquid level of the container disposed thereunder, and that electrolyte always flows only in one of the two syphon lines or in none of the syphon lines. This leads to the permanent interruption of the current flow in the peripheral region between the outlet and the inlet of the electrolysis plant. If instead a switching of valves would be employed, small amounts of electrolyte wetting the walls inside the valve could already lead to a disturbing electrical conductivity.
The process can be employed in various types of electrolysis plants, which are used e.g. for metal recovery, metal refining, electrosynthesis or electroplating.